Phobos

Phobos is the largest out of Mars' 2 moons. It is 27 by 22 by 18 km in diameter. It orbits Mars 3 times a day!

Phobos is getting closer to Mars at a rate of 1.8 meters every 100 years. This means in about 50 million years it will crash into Mars or break up into a ring.

There is a lot of variation in temperature between day and night. In the day, temperatures reach as high as minus 4°C. The lowest temperatures at night go as low as minus 112°C. This variation is due to the fine dust on the surface not being able to hold in the heat.

Taken on 22nd of August 2004 by by ESA's Mars Express.

This is one of the highest resolution photos taken of Phobos to date.

Credit: ESA/DLR/FU Berlin (G. Neukum).

This picture was taken by Mars Global Surveyor in 1998.

It shows a close up of Phobos' largest crater called Stickney which is about 10km in diameter.

Credit: NASA, Jet Propulsion Laboratory, Malin Space Science Systems.

Taken on March 23rd, 2008 by the Mars Reconnaissance Orbiter.

You can see the Stickney crater on the right hand side. It is the largest crater on the moon.